Error: expected type-specifier before ‘ClassName’

For future people struggling with a similar problem, the situation is that the compiler simply cannot find the type you are using (even if your Intelisense can find it).

This can be caused in many ways:

  • You forgot to #include the header that defines it.
  • Your inclusion guards (#ifndef BLAH_H) are defective (your #ifndef BLAH_H doesn’t match your #define BALH_H due to a typo or copy+paste mistake).
  • Your inclusion guards are accidentally used twice (two separate files both using #define MYHEADER_H, even if they are in separate directories)
  • You forgot that you are using a template (eg. new Vector() should be new Vector<int>())
  • The compiler is thinking you meant one scope when really you meant another (For example, if you have NamespaceA::NamespaceB, AND a <global scope>::NamespaceB, if you are already within NamespaceA, it’ll look in NamespaceA::NamespaceB and not bother checking <global scope>::NamespaceB) unless you explicitly access it.
  • You have a name clash (two entities with the same name, such as a class and an enum member).

To explicitly access something in the global namespace, prefix it with ::, as if the global namespace is a namespace with no name (e.g. ::MyType or ::MyNamespace::MyType).

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